B.4.1. Flashcards
(18 cards)
Habitat
An organism’s habitat is the physical place or environment in which it lives. Organisms show a preference for a particular habitat type, but others are more specific in their requirements than other.
The physical conditions/abiotic factors influence the habitat in which an organism lives, these include:
- Humidity
- Sunlight
- Temperature
- Salinity
- pH (acidity)
- Sunlight
- Water availability
- Soil
- Air
- Rainfall
Each abiotic (physical) factor may be well suited to the organism or it may present it with problems to overcome
To describe the habitat of a species, we need to look at:
- Geographic location → A specific area
- Physical location → The environment and abiotic factors.
- Ecosystem → All the biotic and abiotic factors and their relationships in the particular area.
Habitats can be classified as:
- Terrestrial habitats
- Aquatic habitats
Adaptations
Adaptation is an inherited characteristic of an organism that makes it better suited to its environment and increases its chances of survival and reproduction .
These are genetic traits that evolve through natural selection or mutation
The process of adaptation is important for the survival of a population of species and plays an important role in the evolution of life on Earth.
Species distribution/abiotic factors
Species distribution refers to the geographic location and range of occurrence of a particular species. This can be influenced by a variety of factors, including the range of tolerance of a species for different abiotic factors.
Certain species are adapted to specific abiotic conditions, such as extreme temperatures , low water availability, or acidic soil, whereas others may not be able to survive in these conditions and will be limited to regions that have more favourable abiotic conditions.
Abiotic variables can also influence the interactions between different species in an ecosystem
No species is capable of surviving under all the varying conditions found on Earth because of the tolerance range, this creates a wider distributions of species on the planet.
Coral reefs description
- Corals are marine invertebrates that typically grow in colonies.
- Corals are animals not plants
- Corals are slow-growing
- Corals cam come in various colors
- Some coral species have the ability to regenerate their skeletons.
Coral reefs are underwater structures made up of the calcified skeletons of coral polyps. Coral reefs are diverse ecosystems that are home to many marine organisms such as:
- Fish
- Crustaceans
- Molluscs
- Sponges
- Algae
Coral reefs provide important ecosystem services to humans, like food production, costal protection, and tourism.
Conditions for coral reef formation
Coral reefs are fragile ecosystems and require very specific conditions to survive. Coral reefs are especially sensitive to changes in abiotic conditions, they are as follows:
- Water depth: Coral reefs can grow in shallow waters, typically between 2 and 45 meters, where sunlight can penetrate and support the growth of algae.
- pH: Coral reefs thrive in water with a pH between 8.0 and 8.4
- Salinity: Coral reefs need a stable salt concentration typically from 30 to 37 ppt. Most reef-building corals also require very saline water ranging from 32 to 42 ppt.
- Water clarity: The water must be clear so that a maximum amount of light penetrates it. This is because most reef-building corals contain photosynthetic algae; called zooxanthellae, that lives in their tissues and they need light to produce food. The coral and the algae have a mutualistic relationship, the coral provides the algae with a protected environment and compounds for photosynthesis. In return the algae produce oxygen and help the coral with removing wate products.
- Temperature: Most reef-building corals grow around 23ºC-29ºC.
Coral reef adaptation
Because coral reefs have such a dynamic ecosystem which serve as a habitat for many species, the organisms in coral reef ecosystems have developed a variety of adaptations to survive their challenging environment. Some of these adaptation include:
- Symbiotic relationships: Many species in the coral reef ecosystem form symbiotic relationships with other species, and example of this is the zooxanthellae algae and the corals said before.
- Camouflage: Some species in coral reef ecosystems, like octopuses, have developed unique color patterns that allow them to blend into their surrounding to avoid predators
- Protective covering: Certain types of snails and sea urchins in the coral ecosystem have developed hard, protective shells to help them survive.
- Stingers and spines: Many species in coral reef ecosystems have developed stingers or spines to deter predators and protect themselves.
- Reproductive strategies: Different species have evolved different reproductive strategies to ensure the survival of their species. Some species reproduce by laying eggs, while others use asexual reproduction.
Coral reefs are under threat from a range of human activities, including climate change, pollution, overfishing, and coastal development. These are casing coral bleaching and death, leading to the degradation of coral reef ecosystems.
Efforts to protect and conserve coral reefs include:
- Establishing marine protected areas
- Promoting sustainable fishing practices
- Reducing greenhouse gas emissions to mitigate the impacts of climate change.
Sand dunes habitat
Sand dunes are created by the accumulation of sand that has been carried inland from the beach by onshore wind and trapped by debris or plants. This accumulated sand provides a good habitat for beach grasses that that a strong, horizontal roots that help it stabilise the collected sand, allowing more sand to settle on top.
Specific plant species have adapted to the unstable conditions of sand dunes, one of these being marram grass having the following adaptations:
- Tolerance to drought: Marram grass has a deep root system that allows it to access water and nutrients even during long periods of drought.
- Tolerance to salt: Marram grass can tolerate high levels of salt in the soil, making it ideal for growing in sand where other plants would not survive
- Root adaptations: The roots of marram grass are strong which allows them to anchor themselves firmly in the sand to resist erosion from wind and waves.
- Leaf adaptations: The leaves of marram grass are strong and have a leathery texture. The leaves are rolled in on themselves to that stomata are tucked away in pits withing the curve. These features reduce water loss through transpiration, helping the plant to conserve water.
- Sand-binding: Marram grass has the ability to trap sand particles with its roots and stems. This helps to stabilize sand dunes and prevents erosion.
- Rhizomes: Marram grass has rhizomes which are horizontal underground stems that grow below the surface of the sand. The rhizomes of marram grass are an important adaptation that allows the plant to spread, anchor itself in the sand, access water and nutrients, and help stabilise sand dunes.
Mangrove forest habitat
Mangroves develop where there is a mixture of saltwater and freshwater, and the water level fluctuates with the tides. Mangroves are difficult places for plants to survive due to high levels of salinity in their environment, but some plants species have adapted to the environment such as Rhizophora apiculata.
- Salt tolerance: Rhizophora apiculata* is a halophyte which means it has the ability to tolerate high levels of salt in soil and in the water is ideal for a mangrove ecosystem.
- Root adaptations: The roots of Rhizophora apiculata are specialised structures called pneumatophores that grow vertically from the soil. The pneumatophores help to provide the roots with oxygen even when the soil is waterlogged.
- Flood tolerance: Rhizophora apiculata is able to survive in areas that are frequently flooded. This is achieved through the development of stilt roots that support the tree and keep it above the water.
- Propagation: Rhizophora apiculata has a unique method of propagation in which the seeds germinate and begin to grow while still attached to the parent tree. This allows the tree to establish itself in new areas without being dispersed by water.
Range of tolerance
Range of tolerance refers to the range of environmental conditions, within which an organism can survive and function optimally. Organisms have a specific range of tolerance to each environmental factor, beyond which they may experience stress or even death, this varies among different species. For example, if a plant is exposed to extreme temperatures outside of its range of tolerance, it may experience wilting, leaf drop or even death.
EXAMPLES OF ANIMALS WITH THEIR PREFERRED RANGE OF TOLERANCE:
- Lion → Seasonal rainfall, high temperatures.
- Polar bear → Extremely low temperatures, high salinity
- Chimpanzee → High humidity, high rainfall, and relatively stable temperatures.
- Kangaroo → Low rainfall, high temperatures and frequent droughts
- Emperor penguin → Extremely low temperatures, high winds
- Grizzly bear → Moderate to high rainfall, cold winters and warm summers
Range of tolerance can be affected by environmental changes, such as climate change, pollution or habitat destruction. If the environmental conditions change beyond a species’ range of tolerance, it may be forced to migrate to more suitable areas or face extinction.
When one or more limiting factors such as range of tolerance are in short supply, it can have a significant impact on the distribution, abundance and diversity of species withing an ecosystem.
Biomes
A biome is a large community of plants and animals that occupy a distinct geographical region and are adapted to its climate and other environmental condition. Biomes are characterized by the dominant vegetation, animals, and climate patterns.
The main terrestrial biomes are:
- Tropical rainforest
- Temperate forest
- Taiga
- Grassland
- Tundra
- Hot desert biomes
The 2 main abiotic factors that determine the type of biome in a region are temperature and rainfall pattern.
- Temperature
Temperature has a direct impact of the distribution of biomes because it affects the rate of biological processes such as photosynthesis, growth, and metabolism. - Rainfall
Determines the availability of water for plants and animals.
Every biome is defined by climate and therefore, the same biome can occur in geographically different locations with similar climates.
Ecosystems
A biome is a broader and larger defined area while an ecosystem is a smaller more specific area. Ecosystems can exist in a variety of climates and can be influenced by many other factos besides latitude, like altitude, topography, and human activity.
Types of biomes
These are the different climatic conditions and limiting factors that have resulted in the formation of the main six different terrestrial biomes:
- Tropical forest biome
- Temperature: High (20-30ºC)
- Precipitation: High (1500-2500mm)
- Light intensity: High
- Seasonal variation: Low (relatively constant climate throughout the year)
- Grassland biome
- Temperature: Moderate to high (10-25ºC)
- Precipitation: Low to moderate (250-1000mm)
- Light intensity: High
- Seasonal variation: High (with hot summers and cold winters)
- Taiga biome
- Temperature: Low to moderate (-20-10ºC)
- Precipitation: Moderate (400-900mm)
- Light intensity: Low to moderate
- Seasonal variation: High (with long, cold winters and short, cool summers)
- Temperate biome
- Temperature: Moderate (5-20ºC)
- Precipitation: Moderate to high (500-1500mm)
- Light intensity: Moderate
- Seasonal variation: Moderate (with less pronounced seasons)
- Tundra biome
- Temperature: Low (-30-10ºC)
- Precipitation: Low (100-500mm)
- Light intensity: Moderate to high
- Seasonal variation: High (with long cold winters and short cool summers.
- Desert biome
- Temperature: High (20-40ºC)
- Precipitation: Low (50-250mm)
- Light intensity: High
- Seasonal variation: Low (with only slight variations in temperature and rainfall throughout the year)
Abiotic factors that affect the growth of plants
Plants are highly sensitive to abiotic factors such as:
- Temperature
- Water availability
- Atmospheric gases
- Light intensity
- Soil nutrients
So for this plants need to adapt to survive in harsher habitats. Some of these are:
- Insufficient light:
- Ferns and shade-tolerant trees grow larger, thinner leaves and increase chlorophyll content to maximise light absorption.
- Too much light:
- Succulents and cacti have thick, waxy skin that helps them retain water and reflect sunlight.
- Extreme high temperatures:
- Tomato plants have developed heat shock proteins to protect against high temperatures.
- Inadequate water supply:
- During drought, rice plants can reduce water loss by closing their stomata.
- Poor soil quality
- Legumes have developed symbiotic relationships with nitrogen-fixing bacteria to obtain nitrogen from the air.
Abiotic factors that affect the growth of animals
Animals are also highly sensitive to those abiotic factors and have also adapted to survive in those environments:
- Extreme temperatures:
- Polar bears and penguins have thick layers of fur or blubber to insulate them from extreme cold.
- Fluctuations in water levels
- Camels and kangaroo rats store water in their bodies to survive in arid environments
- Changes in light
- Bats and owls are active at night to avoid predators and take advantage of prey that are active at night.
- Changes in food supply
- Herbivores have adapted to have specialised teeth or digestive systems to extract nutrients from tough plant material
- Climate patterns
- Bats and ground squirrels hibernate during the winter months too conserve energy and survive in colder temperatures.
Transect lines for sampling
The transect line method is a sampling technique used in ecology to gather data on the distribution and abundance of plants and animals in a particular area in correlation to the abiotic variables. It involves establishing a straight line across a particular habitat and then taking measurements or samples at regular intervals along the line.
First, a tape measure or rope is put in a straight line across the habitat. along the line, measurements or samples are taken at regular intervals. The measurements can include things like plant species height, leaf area, soil moisture, animal abundance, etc.
There are 3 different methods of using transect line method for sampling.
- Belt transect: Used to study the distribution and abundance of organisms in a particular habitat by placing a long, narrow belt over the area of interest and counting the number of individuals within the belt.
- Observational transect: Used in environmental monitoring to observe and record data along a designated linear path or transect in a specific habitat or ecosystem
- Line intercept sampling: Used to measure the abundance and distribution of plant species in a particular habitat by recording the points where a line or tape intersects with plant stems or leaves.
Sensors and data loggers
Sensors are devices that measure physical or chemical properties such as:
- Temperature
- Pressure
- Sound level
- Light intensity
- Humidity
Data loggers are electronic devices that record data from sensors over time.
Advantages of data loggers and sensors are:
- They can provide continuous and precises measurements of physical or chemical properties
- They can operate in hazardous or remote environments where human observation is impractical or dangerous.
- They can provide real-time data that can be analysed and acted upon quickly.
- They can take multiple readings quickly.
Adaptations to life in hot deserts
Deserts are characterised by:
- High temperatures during the day
- Low temperatures during the night
- Lack of vegetation
- Lack of water
- Extreme dryness
These conditions make it difficult for most plants and animals to survive, those who do need to be well adapted to the harsh desert climate. Examples include:
- Ocotillo
- Deep root system which allows it to access water from deep in the soil and additional horizontal root system which allows it to quickly absorb even small amounts of precipitation
- Greenish chlorophyll-containing bark allows it to carry out photosynthesis even when there are no leaves present
- Long thorny stems can expand to store water during droughts, allowing it to survive when water is scarce; thorns also serve as a deterrent to herbivores.
- Leaves sprout after rainfall to perform photosynthesis
- Vibrant red flowers attract pollinators for reproduction
- Gila Monster
- Unique ability to store fat in its tail helping it survive long periods of time without food
- Skin is covered in bumpy scales, which help it retain moisture
- Slow metabolic rate allowing it to go for long periods without food and water
- Powerful jaws and venomous saliva, which it uses to overpower its prey and protect itself from predators
- Venom contains toxins that can cause intense pain and swelling making it a strong creature to encounter in the wild.
Adaptations to life in tropical rainforests
Rainforests are one of the most diverse biomes on the planet and are found in tropical regions around the equator. They are characterised as follows:
- High levels of rainfall
- Warm temperatures
- Humid environment
To thrive in this environment, plant and animal species have adapted to it, examples are:
- Giant Amazon Water Lily
- Large circule leaves which can grow up to 3 meters in diameter are covered in a waxy coating that helps them repel water, allowing them to stay afloat on the surface of the water.
- The plant’s large flowers open at night and emit a strong fragrance to attract pollinators
- Unique root system that allows it to anchor itself to the muddy bottom of the river and extract nutrients from the nutrient-rich soil.
- Harpy Eagle
- Strong talons to crush the skulls of its prey
- Bread and strong wings that enable it to move through the dense forest canopy with ease and to glide through the air silently.
- Strong and sensitive hearing allowing it to detect the sounds of prey moving through the forest
- Sharp beak that allows it to capture and feed on large prey
- Binocular vision that allows it to accurately judge distances and track fast-moving prey.
